|A diver in full “Level A” protective dive gear.|
Betsy Painter, working in our Ecological Services Program, tells us about an often-unremarked-on problem with shipwrecks.
We’ve all heard tales of legendary sea monsters and mischievous pirates wreaking havoc on ships, sending some to their watery graves. While many of the actual shipwrecks of the past may not have involved mythical aquatic creatures or outlaw sailors, a seldom-told part of the story reveals a danger more real and more deadly than Scylla and Charybdis or Long John Silver. The metallic skeletons of some ships that have managed to evade detection over the years are slowly decaying, potentially threatening the waters of their final resting sites with the environmentally hazardous substances they hold.
This was the case for the ARGO barge—a ship carrying 4,800 barrels of oil that mysteriously sank in 1937 in Lake Erie. An oily sheen developed over the surface of a large patch of water nearly 80 years later after an anchor of a dive boat disturbed the sediment of the lake floor; the source of the oil was moments away from discovery.
|A scan of the ARGO.|
In August 2015—after diving off his boat into the warm, rippling waters of Lake Erie and down into its cooling depths—a shipwreck hunter discovered the missing barge. Tom Kowalczk of Cleveland Underwater Explorers, a recreational diving club, located the ship at the bottom of the lake about 15 miles northeast of Lakeside, Ohio, while performing a sonar search. The National Oceanic and Atmospheric Administration (NOAA) has long sought ARGO because its holdings could cause an environmental disaster on the Great Lakes. Now that it is found, response and restoration efforts are assessing any damage already done and prevent further threats to the environment.
Richard Henry, a U.S. Fish and Wildlife Service biologist, works with the Environmental Protection Agency’s (EPA) environmental response team to provide technical support and advice for operations in the field. Henry’s role is to represent the Service’s goal of protecting endangered and threatened species and other trust resources during the cleanup process.
The initial response effort kicked off in November with commercial divers collecting sediment samples from the perimeter of the ARGO barge. The divers donned full “Level A” protective dive gear, “equivalent to an underwater moon suit,” explains Henry. The sediment samples were sent to a lab and analyzed for petroleum hydrocarbons, semivolatile and volatile organics, and PCBs. The sediment was also screened with direct reading field instruments, and the results suggested they were indeed contaminated with volatile organics. Out of the six to eight oil-filled cells still intact in the vessel, at least two of the compartments were leaking a vintage petroleum product, benzole.
The decision was made to offload the petroleum product from the barge so that no further oil could leak out into the water. “The divers emptied the barge’s contents while it rested on the lake bottom through a process called a ‘hot-tap’ which involves putting a hole in the barge wall and installing a port so a hose can be attached and the contents pumped out,” says Henry. “This time-critical action was aimed at reducing the imminent threat of harm to human health and the environment.”
Now that an empty ARGO no longer poses an imminent threat to humans and the environment, the next step is to evaluate the extent of the contamination and concentration of the benzole in the sediment. This data will help determine the magnitude of risk to fish and birds, as well as humans involved in various activities that may expose them to contaminants. Further response actions will be decided on the basis of the magnitude of the risk, and may include an action to remove or remediate contaminated sediment.
“Due to weather, additional characterization and/or removal actions were suspended until spring or summer of 2016,” says Henry. “The EPA’s Environmental Response Team, the group that I am embedded in, offered assistance to further characterize the sediment and determine the risk to human health and the environment.”
It looks like for now, ARGO will continue to haunt the bottom of Lake Eerie until its final destiny is decided, leak free and full of harmless lake water.